Single power stroke thruster with split cartridge case lock



Nov. 17, 1959 w. J. KROEGER ETAL 2,912,901

SINGLE POWER STROKE THRUSTER WITH SPLIT CARTRIDGE CASE LOCK Filed Feb. 15, 1957 INVENTORS WILLIAM J. KROEGER BY SYLVAN D. ROLLE United States SINGLE POWER STROKE THRUSTER WITH SPLIT CARTRIDGE CASE LOCK William J. Kroeger and Sylvan D. Roll, Philadelphia, Pa.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without payment of any royalty thereon.

This invention relates to a cartridge actuated single stroke thruster having a lock responsive to fluid pressure and has for an object to eliminate externally applied energy heretofore necessary to unlock a thruster of the type used on aircraft and elsewhere. Another object is to enhance the safety in use of such a thruster by eliminating the danger of internal pressure building up high enough to endanger the walls bursting. Yet a further object is to provide such a device of improved simplicity in construction and operation, which is adapted to give more nearly accurately predictable results.

According to this invention, a longitudinally slotted cartridge case has its walls yieldable radially inwardly to disengage them from an inner tube of the thruster on firing to allow longitudinal travel of the inner tube under a load while the cartridge case is also held against opposite movement by a base cap connection with an outer casing.

Fig. 1 shows a longitudinal section through a preferred embodiment of the present invention.

Fig. 2 is a top plan view of the cartridge case 13 without any propelling charge therein.

Fig. 3 is a longitudinal section through a modified embodiment of the present invention.

In the embodiment illustrated in Fig. 1 there is provided an outer casing 10, an intermediate casing or tube 11, and an inner tube 12 for applying power to the load to be moved. Within the cartridge case side walls 13 is a propelling charge preferably of a monoblock type 14. The cartridge case is provided with a base flange 15 which extends under a portion of a base cap 16 threaded at 17 to the outer tube 10. A breech closure 18 is removably secured to the base cap 16 for either a percussion or electric type primer. The monoblock propelling charge may extend above the top of the cartridge case side walls or may end adjacent to that top according to the requirements. The outer surface of the side walls of the cartridge case is provided with circumferential ribs 19 each of which has at least a lower face 20 of the rib inclined at an angle of more than 45 to the horizontal. As shown in Fig. 2, the cartridge case is provided with a plurality of three or more slots extending longitudinally from the upper end of the cartridge case walls down to a convenient position below the ribs but well above the bottom of the propelling charge 14 fitting in the cartridge case 13. The purpose in having at least three slots 21 in the cartridge case 13 is to enable all parts of each segment between such slots to be capable of yielding radially inwardly. If desired, though not necessary, the inner surface of the cartridge case may be provided with one or more fish-hook shaped projections 22 extending into the propelling charge a short distance. An igniter 23 of black powder may be located in the base of the cartridge case between the i gmter and the primer actuator.

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In Fig. 3, similar parts to what is shown in Fig. 1 are designated by a reference numeral the same as such part bore in Fig. 1 except that the letter a has been added. Thus it willbe seen that the cartridge case 13a is threaded to the inner tube 12a with a V-type thread. A non-combustible plug 24 is located in the upper end of the cartridge case for the purpose of holding the expansible side walls in contact with the threads of the inner tube. On firing, this plug is blown out in order that the walls of the cartridge case may become disengaged from thethreacls of the inner tube and allow the inner tube to be moved upwardly and outwardly.

In operation on firing, pressure in the cartridge case 13 forces the block 14 longitudinally outward removing block 14 as an abutment so that the cartridge case may yield radially inward, the pressuregenerated during burning of the propelling charge produces a pressure upon the closed upper end of the inner tube 12 in order that longitudinal tension in the inner tube is provided and this tension is transmitted to the cartridge case walls. However, the base of the cartridge case is anchored by its flange 15 and the tension in the walls of the cartridge case and inner tube effects a sliding movement upon the inclined faces of the cartridge case ribs and similarly inclined faces on the recesses in the inner tube. This sliding of the inner tube rib faces causes the cartridge case side walls to become disengaged from the inner tube by radial inward movement allowing the inner tube 12 to be moved upwardly under load.

Among the advantages of this invention may be mentioned an elimination of the external energy heretofore needed to unlock a thruster because internal pressure here effects that unlocking. Since such internal pressure unlocks the movable element of the thruster there is no danger of rupture in any part of it. Another advantage is the simplicity in construction and operation whereby fewer parts are needed than has heretofore been suggested. An advantage of importance to those skilled in this art is the fact that the present thruster produces results which are more nearly accurately predictable than is the case with the numerous prior art thrusters.

The term thruster includes catapults and canopy removers for aircraft.

We claim:

1. In a thruster having an outer casing, an inner tube movable longitudinally of said casing under fluid pressure therein, a cartridge case within said tube, a base cap connecting said outer casing and a base flange on said cartridge case, the combination therewith of the improvement for retaining said inner tube against outward movement in advance of firing said cartridge, said improvement including the cartridge case upper portion of its side walls being split longitudinally to be yieldable radially inwardly, peripheral ribs on an outer surface of said split portion, said ribs having at least their lower faces inclined, a lower portion of the inner face of said inner tube being provided with circumferential recesses for oo-operation with said ribs, at least the upper faces of said circumferential recesses also inclined at substantially the inclination of the lower faces of said ribs, and a propellant charge for holding the split walls of said cartridge case expanded with said ribs received within said circumferential recesses until after firing a propelling charge within said cartridge case whereby the application of tension to the inner tube on generation of gas pressure therein applies tension to the split cartridge case walls and the inclined faces of said recesses and ribs efiects a radial inward yielding of said split cartridge case walls to disengage said ribs from said recesses and allow outward movement of said inner tube.

2. A thruster according to claim 1 in which the inner face of said cartridge case side wall is provided with means for interlocking with said propelling charge to preclude relative longitudinal movement'between said charge and cartridge case prior to firing said charge.

3. A thruster according to claim 1 in which said propelling charge isof the ino'noblock type. J l J 4; In a thruster having an'outer casing,'a'n inner tube movable longitudinally of said casing'under fluid pressure therein, a cartridge case within said tube, a base cap connecting said outer casing and abase'flange on said cartridge case, the combination therewith of the improvement for retaining said inner tube against outward movement in advance of firing said cartridge, said improvement including the cartridge case upper portion of its side walls being split longitudinally to be yieldable radially inwardly, peripheral ribs on an outer surface of 'said split portion, said n'bs having at least their lower faces inclined, a lower portion of the inner face of said inner tube being provided with circumferential recesses for co-operation with said ribs, at least the upper faces of said circumferential recesses also inclined at substantially, the inclinationof the lower faces of said ribs, a propellant charge within said cartridge case, and

a substantially non-combustible plug within said cartridge case and adjacent said charge for holding the split walls of said cartridge case expanded with said ribs received within said circumferential recesses until after firing a propelling charge Within said cartridge case whereby the application of tension to the inner tube on generation of gas pressure therein applies tension to the split cartridge case walls and the inclined faces of said recesses and ribseflects a radial inward yielding of said split cartridge case walls to disengage said ribs from said recesses and allow outward movement of said inner tube.

References Cited in the file of this patent UNITED STATES PATENTS 7 Sweden July 27,, 1948 

